Scrape off old EPS facade insulation

Good question, there is a foil after the insulation, whether it is airtight, I doubt. Would the right solution really be to plaster the entire facade in front of the insulation?

What speaks against insulation with mineral wool? It should adapt to the unevenness.

The behavior with moisture speaks against mineral wool, as there can always be some moisture coming through. Wood wool dries better, is more ecological (since local, produced 30 km away) and insulates slightly better in summer. I think I should have chosen blown-in insulation, Zimmermann doesn't do that and I only removed a small piece of facade for surveying. Only now, with more gone, can you see the masonry. I could already start filling, just need scaffolding earlier.

I entered it once into ubakus, 1 cm air layer does not produce condensate, from a building physics standpoint I believe it is less problematic than aligning the vertical battens. Zimmermann says they warp. So, putty after all. The question is with what and do you have to reinforce with such a thin layer? Sackzement?

I am with Sakret (please, this is not an advertisement, just what is available at Obi) whether lime-cement or MAP-L lightweight lime-cement plaster is suitable, Obi also has Laier lime-cement. It should be vapor-permeable, stable, and adhere well. There are 2 variants: normal and lightweight. Does anyone know the differences?